WO2010002370A1

WO2010002370A1 - Compact transmission for a work machine

Info

Publication number: WO2010002370A1
Application number: PCT/US2008/008277
Authority: WO
Inventors: Brian Daniel Durbin; Thomas George Ore; Chad G. Vandenberg; Bradley Allen Merrill; Jeremie J. Peterson; Richard Neville Knowles
Original assignee: Deere and Co
Current assignee: Deere and Co
Priority date: 2008-07-03
Filing date: 2008-07-03
Publication date: 2010-01-07
Anticipated expiration: 2011-01-03
Also published as: EP2307763A4; EP2307763A1; BRPI0822797A2; CN102066809A

Abstract

A compact transmission (12) for a work machine (10) having a center housing (70) for a differential drive (14), speed reduction gear (77) and service brakes (78) extending to a pair of axles (16). A second housing is removably secured to the center housing (72) and contains speed range gears (74), a MFWD drive (41 ) and a creeper gear assembly (50). This housing (72) also contains the lube and hydraulic pumps (76) which are laterally spaced from the drive input. A valve body (88) positioned on top of the center housing provides control of all the valve assemblies. A second housing (82) is secured to the center housing (72) and provides a mounting for a PTO (86) which is driven through the center housing (72) and is positioned for efficient removal and substitution of a variety of PTO options.

Description

COMPACT TRANSMISSION FOR A WORK MACHINE

Field of the Invention

[0001] The present invention relates to work machines, and more specifically to transmissions used in such work machines.

Background of the Invention

[0002] A work machine such as an agricultural tractor may be driven with motive force taking several different forms such as a rear wheel drive, four wheel drive (4WD)₁ mechanical front wheel drive (MFWD), endless track drive and other forms. Transmissions providing outputs of these types also typically provide a power take off or PTO used to drive agricultural processing equipment at an RPM appropriate for the processing equipment. In addition, such transmissions frequently incorporate a creeper gear that provides a substantially lower vehicle ground speed than that obtainable with the normal speed range gears within the transmission. [0003] All these features typically result in a transmission that is substantially elongated, since the various components are stacked axially relative to one another. The axial length of the transmission then becomes a limiting factor in the application of the transmission for tractors for which a compact power train is required. [0004] Accordingly, what is needed in the art is a compact transmission of the above type that performs all the functions expected from a transmission for a work machine.

Summary of the Invention

[0005] In one form the invention is a transmission for a work machine in which the transmission includes a first housing and a differential drive mechanism mounted in the first housing. A second housing is removably mounted to one side of the first housing and supports a plurality of speed range gears. The speed range gears receive a prime mover power input from a direction away from the first housing and have at least a power input to the differential drive mechanism. A third housing is removably mounted to the second side of the first housing and has a mechanism within the third housing providing a secondary power output, the mechanism being driven by the prime mover through the first housing.

[0006] In another form, the invention includes a work machine having a prime mover providing a rotary output. A transmission receives the output from the prime mover. The transmission includes a first housing and a differential drive mechanism mounted in the first housing. A second housing is removably mounted to a one side of the first housing. A plurality of speed range gears are mounted in the second housing and receive the input from the prime mover. The second housing is positioned between the first housing and the prime mover. The speed range gears provide at least a power input to the differential drive mechanism. A third housing is removably mounted to a second side of the first housing and has a mechanism within the third housing providing a secondary power output, the mechanism being driven from the prime mover through the first housing.

Brief Description of the Drawings

[0007] Fig. 1 is an external perspective view of a work machine incorporating a transmission which embodies the present invention;

[0008] Fig. 2 is a partial sectioned view of the transmission shown in Fig. 1 taken on lines 2-2 of Fig. 1 ; and

[0009] Fig. 3 is a perspective view of the transmission of Fig. 1 taken from a different perspective and partially cut away to show the internal components within the transmission.

Detailed Description of the Invention

[0010] Referring now to the drawings, and more particularly to Figs. 1 , 2 and 3, there is shown a portion of a work machine 10 in the form of an agricultural tractor, particularly the rear end drive train of the tractor. Although shown as an agricultural tractor, it is possible that work machine 10 could be in the form of a different type of work machine, such as a construction tractor or forestry machine. [0011] Tractor 10 includes a transmission 12 coupled with a rear end differential 14 which in turn drives a pair of axles 16. Each rear axle 16 includes an outboard hub 18 to which a respective rear drive wheel (not shown) is mounted. Transmission 12 includes a driven shaft 20 which is mechanically coupled with and receives rotational input from an internal combustion (IC) engine 22 shown schematically in Fig. 1. Driven shaft 20 transfers rotational power via appropriate speed range gears to differential 14 which in turn extends from the rear of and provides rotational input power to the rear end differential gear set 26 (see Fig. 2).

[0012] Driven shaft 20 extends through and is rotatably carried by housing 72 which likewise houses and rotatably carries a number of other components. Also positioned within and carried by housing 28 is an idler arrangement 30 which mechanically interconnects between a power input 32 and a power output 34. Referring to Fig. 2, power input includes an input shaft 36 and an input gear 38 carried by input shaft 36. In the embodiment shown, input shaft 36 is in fact the differential drive shaft 24 but could be a different rotatable drive shaft providing input power to idler arrangement 30. Input shaft 36 receives input power from driven shaft 20 coupled with engine 22. [0013] As shown in Figs. 1 , 2 and 3, housing 12 consists of a first housing 70 containing differential 14 and a second housing 72 containing a plurality of speed range gears, generally indicated by reference character 74. Speed range gears 74 are journaled within the housing 72 which is removably connected to housing 70 by appropriate fasteners. As shown in Fig. 2, speed range gears 74 are selectively connectable to drive shaft 24 providing an input to the ring gear 26 of the differential 14. [0014] Also within housing 74 is contained in idler assembly 30 having an input shaft 44 with gear 46 meshing with a gear 38 on shaft 24. Gears 48 mesh with output shaft 40 providing drive to the MFWD 41. As noted particularly in Fig. 2, the idler assembly 30 is laterally spaced from shaft 24 so that the mechanism for the gear ratios is placed within a compact overall envelope. A creeper gear assembly 50 is positioned within housing 72 and housing 70 and is also laterally spaced from shaft 24 so that the mechanism takes up otherwise unused space within housing 70. As shown particularly in Fig. 2, the idler mechanism 30 is positioned generally below shaft 24 so as to provide room for a hydraulic and lube pump assembly generally indicated by reference character 76. These are spaced laterally from the center of housing 72 but fit within the overall axial envelope of the housing. The hydraulic and lube pump assembly 76 provide lubrication to the internal gears and components of the transmission 12 but also provide hydraulic fluid under pressure for other components of the work machine 10. [0015] The housing 70, in addition to containing the differential assembly 14, has various gear reduction components 77 and service brakes 78 mounted in housing 70. End plates 80 integral with axles 16 are provided at the lateral ends of housing 70. [0016] The transmission assembly 12 contains a third housing 82 removably secured to housing 70. Housing 82 includes a hitch 84 and contains an input drive 87 for a PTO generally indicated by reference character 86 in Fig. 3. The drive for PTO 86 extends from housing 72 through housing 70 into PTO 86. The drive 87 is offset relative to the differential gear set 26 so that the drive can pass through. The PTO provides a predetermined RPM ratio with respect to the engine input shaft 22 and is adaptable to be coupled and decoupled as needed for a particular operating duty cycle. The PTO 86 generally occupies no more than the axial depth of the housing 82 to further enhance a compact overall package.

[0017] A valve distribution body 88 is positioned on top of the housing 70 to provide a central location for the valving functions of the transmission 12 and receives pressurized fluid through internal passages (not shown) from the hydraulic and lube pump assembly 76. The return fluid for the valve distribution body 88 is directed through the PTO 86 to provide efficient lubrication without un-necessary pressurization of fluid.

[0018] The overall arrangement of the components within the transmission 12 results in an architecturally compact transmission where the components are positioned so that a minimal overall transmission length is achieved. Extra components are positioned laterally either to the side, as with the hydraulic and lube pump assembly 76 or downward, as with the idler assembly 30 for the MFWD 41 so as to fill the non-axial space of the housing 72. This arrangement of the components permits the application of the transmission 12 into a wider range of work machines. At the same time, the transmission 12 provides all the features that are normally found in transmissions of this type. The arrangement of the parts within the transmission generally results in a transmission package that is roughly half the axial length of prior art transmissions. Furthermore, the provision of the speed range gears 74 and MFWD drive within the housing 72 allows for efficient subassembly and subsequent connection to housing 70 which contains the differential 14 and associated speed reduction gears and service brakes 78. The provision of the housing 86 on the opposite side of housing 70 allows for rapid selection of alternate option packages by simply fastening and un-fastening housing 86.

[0019] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.

Claims

1. A transmission for a work machine, said transmission comprising: a first housing a differential drive mechanism mounted in said first housing; a second housing removably mounted to one side of said first housing; a plurality of speed range gears in said second housing receiving a prime mover power input from a direction away from said first housing and having at least a power input to said differential drive mechanism; a third housing removably mounted to a second side of said first housing; and a mechanism within said third housing providing a secondary power output, said mechanism being driven by said prime mover through said first housing.

2. A transmission as claimed in claim 1 , wherein said secondary power output is a power take off unit (PTO).

3. A transmission as claimed in claim 2, further comprising a hitch integral with said third housing.

4. A transmission as claimed in claim 1 , further comprising a drive extending forward towards said prime mover from said second housing for driving a mechanical front wheel drive (MFWD).

5. A transmission as claimed in claim 1 , further comprising hydraulic and lube pumps integrated into said second housing and spaced laterally from said power input and supplying lubricant for said transmission and hydraulic fluid for actuation and lubrication purposes.

6. A transmission as claimed in claim 1 , further comprising axles extending laterally from said differential unit and removably connected to said first housing.

7. A transmission as claimed in claim 6, further comprising service brakes inboard of said axles and contained within said first housing.

8. A transmission as claimed in claim 2, further comprising a lubricant pump integral with said second housing and supplying lubricant to the speed range gears and differential and a fluid distribution valve mounted to said first housing, said PTO being lubricated from the return fluid from said distribution valve on said first housing.

9. A transmission as claimed in claim 1 , further comprising a creeper gear positioned within said first and second housing.

10. A transmission as claimed in claim 10, further comprising a shaft extending from said second housing to said third housing and being offset from said differential drive mechanism.

11. A work machine comprising: a prime mover providing a rotary output a transmission receiving the output from said prime mover, said transmission comprising: a first housing; a differential drive mechanism mounted in said first housing; a second housing removably mounted to one side of said first housing; a plurality of speed range gears in said second housing receiving the input of said prime mover, said second housing being positioned between said first housing and said prime mover, said speed range gears having at least a power input to said differential drive mechanism; a third housing removably mounted to a second side of said first housing; and a mechanism within said third housing providing a secondary power output, said mechanism being driven from said prime mover through said first housing.

12. A work machine as claimed in claim 11 , wherein said secondary power output is a PTO.

13. A work machine as claimed in claim 12, further comprising a hitch integral with said third housing and adjacent said PTO drive.

14. A work machine as claimed in claim 11 , further comprising a drive for a mechanical front wheel drive (MFWD) within said second housing.

15. A work machine as claimed in claim 11 , further comprising a hydraulic and lube pump integral with said second housing and spaced laterally from said power input and supplying lubricant for said transmission and hydraulic fluid for actuation and lubrication purposes.

16. A work machine as claimed in claim 11 , further comprising a pair of axles extending laterally from said first housing.

17. A work machine as claimed in claim 16, further comprising service brakes in said first housing and inboard of said axles.

18. A work machine as claimed in claim 12, further comprising a lubricant pump integral with said second housing and supplying lubricant to the speed range gears and differential and a fluid distribution valve mounted to said first housing, said PTO being lubricated from the return fluid from said distribution valve on said first housing.

19. A work machine as claimed in claim 11 , further comprising a creeper gear positioned within said second and first housing.

20. A work machine as claimed in claim 12, wherein the drive for said PTO is offset from the differential drive mechanism.